Railway traffic controlling system



Oct. 2, 1934. J STEPHENSON 1,975,137

RAILWAY TRAFFIC CONTROLLING SYSTEM Filed Dec. 19, 1931 1' nu-1| a I E 'N 1 D-J i I g g a I IVENT R ATTORNEY Patented Get. 2, 1934 UNITED STATES RAILWAY TRAFFIC CONTROLLING SYSTEM James E. Stephenson, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N. Y.

Application December 19, 1931, Serial No. 582,100

7 Claims.

This invention relates to traiiic controlling systems for railroads, and more particularly pertains to the remote control of power operated track switches in interlocking systems.

The present invention proposes to provide a control system for use with a power operated track switch, in: which a' switch machine for operating the track switch is controlled in such a manner that an'operation of the track switch is prevented from being initiated during the occupied condition of its associated detector track section; and also in which an operation of the track switch already initiated'is allowed or caused to be completed even upon the entrance of a train into "the associated detector track section irrespective of contemporaneous control conditions set up by the operator in the tower. 'Various' other features, advantagesand characteristic functions of the present invention will be-in part obvious from the accompanying draw ing', and in part pointed out, as the description progresses.

In describing the invention in detail, reference will'be made to theaccompanying drawing which illustrates in a simplified and diagrammatic manner thecircuits and parts of a switch machine control system embodying the present invention, as applied'to'a single railroad track switch. e 1 With reference to the accompanying drawing, a railroad'track switch TS is indicated as being operated by a switch machine SM which may be of any suitable type, as disclosed for example in the patent to W. K. Howe, No.- 1,466,903, dated September 4, 1923. This switch machine has associated therewith a control relay CR tog'ether with normal and reverse contactors N and R respectively for governing the normal and reverse operating'circuits of the switch machine motor having the usual armature A and field winding F. These relays may be suitably located within the switch machine structure or may be provided with a separate housing, as desired. Inasmuch as these relays serve to govern the operating circuits of the switch machine motor, the usual switch machine pole changer contacts and pole changer coils are omitted.

The switch machine is preferably provided with suitable point detectorcontactsand associated mechanism-,as shownfor example in the patent to C.'S. Bushnell No. 1,517,236, dated November 25, 1924, which mechanismis' employed forcontrolling the'contactors N and R and for controlling suitable switchposition repeating relays (not shown),- 'I'he pointdetector contacts for controlling the contactors N and R include two pair of fixed contacts 5 and 6 together with movable contacts '7 and 8. The movable contact '7 makes contact between, the fixedcontacts 5 when in normaland mid stroke positions, while the movable contact 8 makes contact between the fixed contacts 6 when in reverse and mid stroke positions. These movable contacts 7 and 8 are jointly operated by the track switch TS and the switch machine SM, so as to assume normal or reverse positions when the track fswitchis in normal or reverse positions and looked by the switch machine, and so as to assume intermediate or mid stroke positions whenever the trackswitch is being operated by the switch machine SM or whenever the track switch TS is unlocked. Y

The control relay CR is preferably of the two position polarized type, that is, its contacts are operated to opposite positions by the application of potential of opposite polarities, and these contacts are held in their last operated position by some suitable means such as a magnetic stick type structure or a suitable mechanical toggle device. The contacts, 9 and 10 ,of the control relay CRare preferably of the break beyond center type, as the operating circuit for the control relay CR includes the contact 9 which requires that the operating circuit be completed until the mechanism of the control relay has been operated sufliciently to insure that the toggle device or other means will complete the operation of the contacts to the new extreme position. One relay having the above mentioned characteristics is disclosed, for example, in the pending application of J. F. Merkel Ser. No. 536,917, filed May The contactors N and R are assumed to be of the usual tractive type each one of which has the usual characteristics of'this type of device-in that thedegree of energization tohold its contacts in energized positions is a smaller valuethan that required to actuate its contacts to picked up positions. These contactors have been associated with the control relay CR and the point detector contacts in such a way that an auxiliary holding circuit iscompleted through a limiting resistor LR. whenever the track switch TS is in mid stroke or is unlocked. The limitingresistor. LBfis of such a'value that the current which flows in the auxiliary holding circuit is of insufiicient value. to cause the contacts of the contactors tobe actu' ated to energized positions, but is of sufiicient value to maintain the contacts of either contactor after they have once been energized or actuated to picked up positions, as explained more in detail hereinafter.

Associated with the track switch TS is the usual detector track section having a track bat tery and the usual track relay T. It is also to be understood, that there are suitable signals associated with the track switch TS for governing traffic thereover and that they are suitably interlocked with the switch machine control either electrically or mechanically, all of which has been omitted for the sake of simplifying the disclosure of the present invention.

A suitable source of energy is'located in the tower or at a power station, for supplying energy to the various switch machines and other traffic controlling devices of the interlocking system. For this purpose, a battery BT has been illustrated as supplying energy to the bus wires 12 and 14, from which energy is taken both at the tower and at the switch machine for governing the track switch TS.

A switch machine lever SML is provided in the tower for governing the application of energy to the polarized circuits for operating the control relay CR and the contactors N and R. Although the switch machine ccntrol lever SML has been shown as a simple free lever, it is to be understood that it may be of any suitable type known in the railway signaling art, as for eX- ample, the usual interlocked control lever having mechanical interlocking connecting it with the other devices in the system, or suitable electrical interlocking may be employed in connection therewith. Also, suitable detector locking, ap-

. eration of trains over the track switch TS all of which has been omitted for convenience in de scribing the present invention.

It is believed that the nature of the invention, its advantages and characteristic features can be best understood with further description being set forth from the standpoint of operation.

Operation With the system in the normal conditions illustrated, where the track switch TS and switch machine control lever SML are in correspondence, the control relay CE is shunted thereby being protected from the chance application of foreign currents; and similarly, the contactor circuits then connected with the lever are likewise short circuited.

For example, the shunt circuit for the control relay CR is completed from the negative bus 14, through wires 16 and 17, contact 18 of lever SML in a normal position, line wire 19, windings of relay CR, wire 20, polar contact 9 of control relay GR in a left hand position, wire 21, back to the negative bus 14. The shunt circuit for the contactor line circuit is completed from the negative bus 14, through wires 16 and 22, contact 23 of switch machine control lever SML in a normal position, line wire 24, front contact 25 of track relay T, wire 26, polar contact 10 of relay GR in a left hand position, limiting resistor LR, wire 27, point detector contacts 5-7, wire 28, winding of the reverse contactor R, wire 29, back to the negative bus 14.

'Whenever the detector track section associated with the track switch TS is unoccupied by a train and the track relay T is energized, the switch machine SM may be controlled by the lever SML so as to operate the track switch TS to a new position or back and forth between its opposite positions, as desired.

Let us assume that the operator moves the switch machine lever SML to a reverse dotted line position. This causes the application of opposite polarities to the two terminals of the control relay CR, thereby causingits contacts to be operated to opposite positions. This circuit is completed from the positive bus 12, through wires 30 and 31, contact 18 of lever SML in a reverse position, line wire 19, winding of control relay CR, wire 20, polar contact 9 of relay CR in a left hand position, wire 21, to the negative bus 14. The current which flows in this circuit actuates the contacts of the relay CR to right hand positions, and such completion of operation of the contacts is insured as the contact 9 is a break beyond center contact, preferably accomplished by a suitable toggle device which positively takes eifect to com plete the operation of the contacts to new positions and hold them-in such positions. The momentum of the relay mechanism also serves to insure thatthey are operated to their new positions. As soon as the contacts of the control relay CR assume their new positions, the windings of the control relay are shunted through a circuit from the positive bus 12, through wires 30 and 31, contact 18 of lever SML in a reverse-position, line wire 19, windings of control relay CR, wire 20, polar contact 9 of relay CR in a right hand position, wires 32 and 33, to the positive bus 12.

. With the contacts of the control relay CR now in. correspondence with the contacts of the switch machine lever SML and the point detector contacts, an energizing circuit is completed for the windings of the reverse contactor R from the positive bus 12, through wires 30 and 34, contact 23 of switch machine lever SML in a reverse position, line wire 24, front contact 25 of track relay T, wire 26, polar contact 10 of control relay CR in a right hand position, wire 27, point detector contacts 57, wire 28, windings of the reverse contactor R, wire 29, to the negative bus 14. The current which flows in this circuit is sufficient to cause the contacts of the reverse contactor R to be actuated to picked up or energized positions.

The closure of front contact 35 causes current to be supplied to the armature A and field winding F from the positive bus 12, through wires 33, 36 and 37, front contact 35 of reverse contactor R, field winding F, back contact 38 of normal contactor'N, windings of the armature A, wire 39, to the negative bus 14. The current which flows in this reverse operating circuit causes the armature A to revolve in a reverse direction for the operation of the track switch TS through the medium of the switch machine mechanism to a reversed locked position. In other words the switch machine, when operated by the motor, unlocks the track switch TS, operates it to the new position and again looks it all in the usual manner as specifically described in the above mentioned patent to W. K. Howe, No. 1,466,903, dated September 4, 1923.

During the operation of the switch machine SM the movable contacts 7 and 8 assume mid stroke positions which completes a holding circuit for the contactors. The current which flows in this circuit is of sufficient value to maintain the contacts of the reverse contactor R in their energized positions, but is of insufiicient value to actuate the contacts of the normal contactor N to energized positions. This is due to the proper value chosenfor the limiting resistor LR in accordance with the characteristics; of the contactors'N and R. Hence, front contact 35 and back contact 38 are both maintained closedso as to continue the operation of the switch machine motor. Also, this holding circuit, completed with the track switch and switch machine in mid stroke conditions, is effective only when the track relay T of the detector track section is deenergized. v

Assuming for examplethat the track relay T is deenergized due to the entrance of a train imme-v diately following the initiation of the switch machine into operation'and after the movable contacts 7 and 8 have assumed mid'stroke positions, then the holding circuit is completed from the positive bus 12, through wire 40, windings of the normal contactor N, wire 41, point detector con tacts 6-8, wire 42, limiting'resistor LR, wire 27; point detector contacts 5--7, wire 28, windings of the reverse contactor R, wire 29,- to the negative bus 14. v

It is obvious, that, so long as the track relay-T is energized, this auxiliary holding circuit is not completed, as the reverse contactor R 'is energized through its pick-up circuit and the normal contactor N is shunted or short circuited through a circuit from the positive bus '12,

through wires 30 and 34, contact 23 of switch ma-' chine lever SML in a reverse position, line wire 24, front contact 25 of track relayT, wire 26, polar contact 10 of control relay GR in a right hand position, limiting resistorLR, wire 42,'point detector contacts 6-8', wire 4'1,'windings of normal contactor N, wire 40. back to'the positive bus 12. Thus, the reverse contactor is maintained energized for completing the reverse operation ofthe track switch either through its pick-up circuit, if the detector track sectio'n'is not occupied, 'or through its holding circuit, if "the detector track section becomes occupied, but'in either case, the operation is insured or completion;

It is further noted that-the auxiliaryholding circuit is completed independentlyof the contact 10 of the control relay CR, therefora'should the control relay CR be accidentally or otherwise operated to a new position subsequent to the deenergization of the track'relay T and duringmid stroke operating conditions, that operation "alreadyinitiated would be completed.

However, it is to be understood that the track switch TS maybe reversed in mid stroke whenever the track relay T is energized. This is due to the'fact that movable contacts 7 and 8 are in mid stroke positions during the operation of the track switch, so that operation of thepolar contact 10 to one extreme position or the other causes the energization of that particular contactor corresponding to its last operated position and the deenergization of the other. This closes the proper operating circuit for the motor to accomplishthe-operation of the'track switch: in the direction to which the switch machine lever SML has been last operated.

At the end of the operation of the track switch TS to the reverse 'positionfassuming that the lever SML has been left in the reverse position, and irrespective of whether the detector track section is occupied or not, the contacts 7 and 8 are moved to reverse positions opening the energizing-circuits '(either pickup or holding) for the reverse cont actor R, thereby stopping the ope'ration'of the switch machine motor by open ing its operating circuit at open front contact 35.

It is believed'tha't the operations involved in operating the'track'switch TS from a reverse position to a normal-position will be understood by analogy to the description already given, as such operation is merely the converse of the operation already-described.

Let us assume that the system is the normal 1 conditions illustrated, and that a train is on the detector track section deenergizing the track relay T,-the contro'f. relay CR may be operated in anticipation of the next operation dependent of course upon the automatic signalling associated therewith in accordance with the usual practices, but the switch machine cannot be operated inasmuch as front contact 25 is open and the pickup circuit for the windings of the reverse contactor R. cannot be completed. A similar condition exists when the system is in the reverse condition. Thus, the track switch is adequately protected against initiating a new operation during the occupied condition of its detector track circuit. v

Although the operating circuits of the switch machine including the armature A and field winding F have been shown in a simplified and diagrammatic manner, it is to be understood that suitable blow-out means may be associated with their controlling contacts, and that suitable overload protection may be provided in connection therewith. Aso, if overload protectionis-provided, it may be'of anysuitabletype as shown for example in the application of Hoppe' and Swanton, Ser. No. 474,758, filed August'l2,.l930, which issued as Patent No. 1,877,876 on Sept. 20, 1932, all or" which is considered as preferably employed in actual practice, but which has been omitted to simplify the disclosure for a proper understanding of the'present invention.

Thus, acontrol circuit for power operated track switches has been shown and described, which permits the operation of a track switch by the operator and in accordance with such automatic signalling as may be employed in connection therewith, but'with adequate protection for preventing'the init ation of an operation of a track switch during the occupied condition of its detector track section, and also 'to provide that an operation of a track switch initiated just prior to the entrance of a train into its detector track section may be insured of completion". Having described a switch machine control system' as one specific embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the-number of forms which it may assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims. What I claim is: 1. In combination; a track switch; a switch machine for operating said track switch; a polar control relayhaving a two position contact; a track relay associated with said track switch and having a front contact; point detector contacts having normal,-reverse and mid stroke positions; a source of electrical energy; a normal electromagnetic contactor having two terminals one of whichis connected to the positive terminal theiother terminal :of saidno-rmal contactor to sci said track relay front contact when said two position contact is in correspondence with said point detector contacts in normal and mid stroke positions; circuit means connecting the other terminal of said reverse contactor to said track relay front contact when said two position contact is in correspondence with said point detector contacts in reverse and mid stroke positions; 'manually operable means connecting the heel of said track relay front contact to the opposite terminals of said source of electrical energy and simultaneously actuating said polar relay two position contact to an opposite position, whereby said normal and reverse contactors cause the normal and reverse operation of said switch machine upon, the operation of said manually operable means; and a current limiting resistor for shunting said two position contact of said polar relay, whereby that particular contactor which is then picked up when said front contact of said track relay is opened is held energized, if said point detector contacts are in mid stroke positions.

2. In combination, a track switch, a switch machine for operating said track switch, a control relay having a contact operable to opposite extreme positions, two contactors, point detector contacts jointly operated by said track switch and said switch machine to normal reverse-and mid stroke positions, means applying positive potential to one terminal of one of said contactors and negative potential to one terminal of the other of said contactors, means applying negative potential to the other terminal of said one contactor when said contact of said control relay is in one extreme position and said point detector contacts are in; normal or mid stroke positions, means applying positive potential to the other terminal of said other'contactor when said contact of said control relay is in the other extreme position and said point detector contacts are in reverse or mid stroke positions, and a resistor for shunting the extreme positions of said contact of said control relay.

3. In a control system for railroad track switches; a switch machine for operating a track switch; point detector contacts jointlyoperated by said track switch and said switch machine to normal, reverseand mid stroke positions; normal and reverse contactors, each being actuated only when energized to one degree and each being maintained actuated when energized to another degree, said another degree being less than said one degree; a detector track section associated with said track switch; a control relay having a contact operable to opposite extreme positions; a pick-up circuit for said normal contactor closed when said contact of said control relay is in correspondencewith said point detector contacts in normal or mid stroke positions, and said detector track section is unoccupied, whereby said normal contactor is'energized to said one degree; a pick-up circuit for said re verse contactor closed when said contact of said control relay is in correspondence with said point detector contacts in reverse or midstroke positions, and said detector track section is unoccupied,,whereby said reverse contactor is energized to said one degree; a holding circuit for said normal and reverse contactors closed when said detector track section is occupied only if said point detector contacts are in mid stroke positions, said holding circuit including a current limiting resistor, whereby said contactors are energized to said another degree; and normal and reverse operating circuits for said switch machine governed by said normal and reverse contactors respectively.

4'. In a control system for railroad track switches ;'a switch machine for operating a track switch; point detector contacts jointly operated by said'track switch and said switch machine to normal, reverse and mid stroke positions; normal and reverse contactors, each being actuated only when energized to one degree and each being maintained actuated when energized to another degree, said another degree being less than said one degree; a detector track section associated with said, track switch; a control relay having a contact operable to opposite extreme positions; a pick-up circuit for said normal contact-or closed when said contact of said control relay is in correspondence with said point detector contacts in normal or mid stroke positions, and said detector track section is unoccupied, whereby said normal contactor is energized to said one degree; a pick-up circuit for said reverse contactor closed when said contact of said control relay is in correspondence with said point detector contacts in reverse or mid stroke positions, and said detector track section is unoccupied, whereby said reverse contactor is energized to said one degree; a current limiting resistor connected to shunt said control relay contact, whereby a holding circuit is completedfor energizing said contactors to said another degree when said detector track section is occupied and said point detector contacts are in mid stroke positions; and normal and reverseoperating cir cuits for said switch machine governed by said normal and reverse contactors respectively.

5. In combination; a track switch; a switch machine for operating said track switch, and having a normal contact closed when said track switch assumes the normal or an intermediate position, and a reverse contact closed when said track switch assumes a reverse or an intermediate position; a normal relay which when it assumes its attracted position operates said switch machine toward the normal position; a reverse relay which when it assumes its attracted position operates said switch machine toward the reverse position; a source of current; a resistance unit of ohmic value so that if included in series with either of said relays across/said source will allow sufiicient current to flow to hold up such relay but not enough to pick up such relay; a circuit including said source, said reverse relay, said normal contact, said resistance unit, said reverse contact and said normal relay in series in the order recited; and manually operable means for connecting one or the other terminal of said source respectively to one or the other end of said resistance unit., v

6. In combination; a track switch; a switch machine for operating said track switch, and having a normal contact closed when said track switch assumes the normal or an intermediate position; and a reverse contact closed when said track switch assumesa reverse or an intermediate position; a normal relay which when itassumes its attracted position operates said switch machine toward the normal position; a reverse relay which when it assumes its attracted position operates said switch machine toward the re verse position; a source. of current; a resistance unit of ohmic value so that if included in series with either or both of said relays across said source will allow sufficient currentto flow to hold up such relay but not enough to pick up such relay; a circuit including said source, said reverse relay, said normal contact, said resistance unit, said reverse contact and said normal relay in series in the order recited; a track relay which when deenergized manifests the approach of a train to said track switch; and manually operable means efiective only when said track relay is energized for connecting one or the other ter-' minal of said source respectively to one or the other end of said resistance unit; whereby one or the other of said relays may be picked up only if said track relay is energized but will remain up irrespective of said manually operable means when said track relay is deenergized providing said switch machine assumes an intermediate position.

7. In combination; a track switch; a switch machine for operating said track switch, and having a normal contact closed when said track switch assumes the normal or an intermediate position, and a reverse contact closed when said track switch assumes a reverse or an intermediate position; a normal relay which when it assumes its attracted position operates said switch machine toward the normal position; a reverse relay which when it assumes its attracted position operates said switch machine-toward the reverse position; a source of current; a resistance unit of ohmic value so that if included in series with either or both of said relays across said source will allow sufficient current to flow to hold up such relay but not enough to pick up such relay; a circuit including said source, said reverse relay, said normal contact, said resistance unit, said reverse contact and said normal relay in series in the order recited; a track relay which when deenergized manifests the approach of a train to said track switch; and manually operable means effective only when said track relay is energized for connecting one terminal of said source to one end of said resistance unit or connecting the other terminal of said source to the other end of said resistance unit; whereby one or the other of said relays may be picked up only if said track relay is energized but will remain up irrespective of said manually operable means when said track relay is deenergized providing said switch machine assumes an intermediate position.

JAMES E. STEPHENSON. 

